Regarding drilling holes in the check valve disc.
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Some people say that drilling holes in the check valve is done for the heat pump. Can this avoid the need to design a heat pump line? Will drilling cause the pump impeller to rotate in reverse? Wouldn’t that lead to overload when the pump is started suddenly? I hope experts can offer some guidance.
When the temperature of the medium transported through pipes is greater than 200 degrees Celsius, or when the ambient temperature may be below the pour point or freezing point of the material, and a backup pump is available, it is advisable to install a warm pump pipeline equipped with a flow-limiting orifice plate. The bypass pipe for the heat pump is usually DN20, and it is installed in front of and behind the check valve and isolation valve at the pump outlet. A gate valve or globe valve is installed on this bypass pipe; alternatively, a flow-limiting orifice plate can be used in place of the globe valve. It is also possible to drill a small hole in the disc of the check valve as a substitute for the heat pump pipe. The aperture is determined to be 3% to 5% of the normal flow rate. When the ambient temperature is below the pour point or freezing point of the material, in addition to installing a warm pump bypass, a anti-freezing bypass should also be provided between the inlet and outlet pipes of the pump. The connection point of this bypass pipe to the main pipe should be as close as possible to the shut-off valve, in order to avoid the formation of dead zones.